IP stressers have become a growing challenge for network administrators looking to restrict malicious traffic. These services allow attackers to bypass rate-limiting restrictions by coordinating requests across a large number of IP addresses.
IP booters are services that provide on-demand network attacks from thousands of compromised devices. Customers rent access to this network to carry out denial-of-service attacks that flood targets with more requests than they handle. Stressers achieve this by infecting vulnerable systems with malware that allows remote control. Devices like routers, IoT equipment, and servers get compromised by the thousands to form botnets. The IP Booter operator then coordinates these bots to send whatever type of traffic is requested by their customer against any target. Common attack types include UDP floods, ICMP floods, SYN floods, and more. By spreading these requests across such a vast botnet, the traffic bypasses many conventional rate-limiting and firewall defenses.
Challenges defending against stressers
IP stressers present a serious challenge for defenders because of the scale and distribution of their attacks. Traditional defenses are often configured to detect and limit traffic spikes from a single or small range of IP addresses. But with stresser botnets spanning tens of thousands of IPs, there needs to be a single source address sending enough traffic to trigger alerts. Instead, each bot sends a modest amount of traffic, creating a sizable flood when coordinated.
Stressers also regularly cycle through compromised devices. Old bots get replaced with newly infected ones. So IP addresses seen in one attack will often vanish and get replaced for the next one. This makes blocking traffic based on source even more difficult over time. Taken together, these properties allow stressers to effectively bypass many common restrictions and limits that organizations use to manage their network traffic and prevent denial of service conditions. More advanced techniques are necessary to detect and filter out stresser floods.
Potential defenses
Defending against modern IP stressers requires multi-layered strategies, rather than relying on a single line of defenses.
- Real-time traffic analysis – Instead of just looking at traffic spikes from individual IPs, monitor patterns across your whole network traffic flow using analytics. Stresser attacks have identifiable signatures despite being spread across bot IPs. Detecting these requires holistic views.
- IP reputation filtering – Leverage databases that aggregate reputations and past behavior of Internet IPs. Sites like FIreHOL and Spamhaus track and blacklist IPs that are known to originate attacks and spam. Constantly update blacklists to filter out traffic from disreputable sources.
- Connection rate limiting – Rather than focusing solely on bandwidth usage, enforce thresholds on TCP/UDP connection attempts coming from remote hosts. This catch stresser SYN and UDP floods aimed at exhausting server resources.
- Traffic scrubbing services – Partner with vendors specializing in DDoS protection services. Route your traffic through their cleaning centers to filter out bad traffic before it reaches your network perimeter.
While no single solution is perfect, combining these layers gives a robust defense to deal with the evolving methods of IP stressers. However, attacks will also continue to evolve so staying on top of new threats and capabilities is crucial for keeping defenses effective.